From Computer to DVD – The Easy Way

David Shamah, The Jerusalem Post November 22, 2005

Let's say it just “happened” (those who subscribe to the theory of evolution will have an easier time believing this). You woke up one fine day and just happened to find an 800 Mb file on your computer's desktop, bearing the name of a recently released movie or TV show, with the suffix AVI. What do you do?

Well, according to international law, you should forthwith drag the file to your recycle bin and empty it, thereby un-incrminating your computer from involvement in what's probably an Interpol sting operation to round up people guilty of file trading. You try to convince the data police that you didn't actively download that file when they come around!

On second thought, let's say your file – we'll call it Movie.AVI – turns out to be in the public domain, freely tradeable and copyable from computer to computer. So there's no danger of the record or movie company cops dropping by for a late night visit. And, you can watch said movie all on your computer until you know all the lines by heart. Just open up a movie player, like Windows Media Player or Quicktime Player, sit back and enjoy. We'll even assume that you have the full set of codecs necessary to play the files back on your box. All's well that ends well, eh?

But lets say you wanted something more – more than the 17 inches of CRT or LCD you get when viewing a movie on a computer. You want to have it all – the ability to sit in bed and peck away at your laptop, while watching your movie – on your DVD player.

Now out little story becomes clear – and complicated. Most video files “floating” around on the Internet seem to come in AVI (Audio-Video Interleave), the Microsoft Windows standard video format. The video format for DVDs is different (generally MPEG2), and if you want to watch your AVI movie on a DVD disc, you have to convert the file from one format to the other.

Hence the disclaimer: While the techniques we are going to be describing do not differentiate between files acquired in a “good” or “bad” way, one should be discriminating in not downloading commercially released films that you do not have a legal right to acquire and turn into a DVD (don't look so shocked; what did you expect to read in a newspaper?).

Anyway, back to our technical story. DVD authoring includes the art of converting ubiquitous AVIs into MPEG2 files with attached audio (usually .AC3 Dolby digital), as well as converting digital video movie (DV) files into the same format. There are lots of ways to attack this project – you can do it “easy or “hard,” with the results being “plain” or “fancy.” You can add music, pictures, subtitles - depending on the software you use (and assuming your computer can burn DVDs), you can produce a professional looking product that will play perfectly well on your or anyone else's DVD.

Note that there may be several stages involved in building your DVD, depending on how much time and effort you want to invest in authoring. Unless you have a DVD that can play a variety of video formats, including AVI/DivX (the compression codec used on many AVI files to make them small enough to efficiently download) – there are a number on the market – conversion is a necessary process in preparing your DVD. The bells and whistles, where you add the music, titles, subtitles, etc. - the stuff that most people think of when they here the word “authoring” - are really optional, although we will cover some of the tools and techniques involved in that aspect of the job as well. There is an excellent guide at http://en.wikipedia.org/wiki/List_of_file_formats which lists all the formats in general use not only for video and audio, but also for Web pages, documents, spreadsheets, video game ROMs, etc.

I mentioned the term “codec” earlier in passing, and we have discussed codecs in this column in the past, but a slight refresher on the subject is appropriate here. A codec is short for Coder-Decoder (or compressor/decompresser), used to reduce the size of a file in order to make it easier to upload or download. Codecs, once applied, are “lossy,” meaning that when the file is compressed from its original size, some of the digital data is lost when it gets converted again. So for best quality, it's preferable to install the appropriate codec in the computer in order to view it in your PC's movie player. Without the codec, you'll play the file – but you won't see (or probably hear) anything. The same applies to DVD authoring and conversion programs. The encoding of a file requires a frame by frame playback, in most cases – and if the computer can't “see” the video, it won't get encoded.

As mentioned, most AVI files come with DivX compression, and you can download the playback codec for DivX from http://www.divx.com. Other codecs can be downloaded from http://www.free-codecs.com or http://www.codec-download.com. If you can't get the thing to play, the first thing to do with your movie is to attempt to discover which codecs are necessary for playback. For that, you can download AVIcodec from http://avicodec.duby.info, which will not only tell you which codecs the file needs for playback, but where to download them from as well.

As I may have mentioned, I recently acquired a Mac Mini with a superdrive DVD writer for the express purpose of converting DV movies into DVDs. But the system works just as well for AVI to DVD conversion, so I am going to describe the basic conversion process on a Mac first, and then on a PC. Later we will discuss the advanced authoring techniques involved as well. All that and much, much more next week.

Ds@newzgeek.com